Sawmill head-block.



W. M. WILKIN.

SAWMILL HEAD BLOCK.

APPLIOATION FILED ooT.19, 1911.

Y7].,O6. ,993, v Patented July 1, 1913.

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into engagement with the rack-bar thus holding the rack-bar and knee together until released, and the knee moved back to its normal position. lVhen all of the knees of the saw-carriage are moved backward into line, I have provided projections on the sides of the rear end of the rack-bar in which are placed adjusting screws, by means of' which an accurate adjustment of the rack-bar with relation to the securing dog can be made, so that the last board may he of the required and uniform thickness. llVith this arrangement of mechanism there will be no strain on the hand lever, as is the case with all other set-works wherein all of the shock of loading falls on the link, hand-lever and quadrant, as head-blocks are ordinarily Constructed, thereby causing lost motion and frequent breaking of parts.

In operating head-blocks, the present practice is to recede the knees either by friction gears, or by means of coiled springs on the setting shaft, which, when the dog is released causes the knees to run back Yard for the reception of another log. In most cases where springs are used for this purpose they have to be wound very tightly on the. shaft in order toget tension enough to give the requisite power to move the knees backward when the grooves or ways in the blocks become clogged with gum and dirt; consequently the operator has to labor just that much harder to overcome the tension of the spring in addition to moving the weight of the log; and when friction gears are used they usually wear away rapidly; with my device all this trouble is overcome to a very great extent, and when a spring is used to move the knees backward it is not necessary to keep it wound up so tightly.

The features of my invention are hereinafter fully set forth and described, and are illustrated in the accompanying drawings in which:

Figure l is a side view in elevation of my improved head-block with parts of the knee broken away and one side of the base block removed. Fig. 2 shows a horizontal. section of the knee portion of the head-block on the line min Fig. l, and also shows the upper flanges of the block-beams broken away. Fig. 3 shows a rear view of my improved head-block, partly in elevation and partly in section on the line g/Mg/ in Fig. l, looking toward the front end of the block. Fig. 4 is al detail showing in elevation one of the roller dust shields, detached.

sliding knee, D, will enter and slide longitudinally between them.

In suitable bearings in the bifurcated portion, D, of the knee D, I preferably mount axles, E, upon the ends of which axles I secure rollers, E', which tit and roll in the channels, a, in the beams, A, A, of the headblock, so that the knee, D, is carried freely back and forth on said` rollers, E', in the channels, a, a, ofthe beams, A, A, of the head-block. To cover and protect the rollers, E', from dirt and dust, and to clear away any dirt and dust accumulating in the channels, a, out of the `path of the travel ofk the rollers, E', I preferably provide shields, F, (see Fig. 4) which embrace and inclose the rollers, E', as is clearly shown in Fig. 2, the axles, E, ofthe rollers, E, passing through vertically elongated holes, f, so that the shields, F, will not bear any of the weight of the knee, D, or of the strain exerted thereon during the operation thereof.

Upon the axles, E, of the rollers, E', between the bifurcated lower portions, D', of the knee, D, I mount arack-bar, (l, which is provided with elongated slots, g, through which the roller-axles, E, pass, so that there may be a longitudinal movement o-f the axles, E, therein, and to prevent wear upon the axles, E, and the wall of the slots, g, of the rack-bar, G, I preferably place sleeves, e, on the axles, E, where they operate in the slots, g, as is clearly shown in Figs; l and 3. On the lower edge of the rack-bar, Gr, there is a continuous rack, G, adapted to be engaged by the gear-pinion Il, o-n the settingshaft, H, and on the upper edge of the rear portion of the rack-bar, G, I place a section of rack-gear, g', for the purpose hereinafter set forth, and on the rear end of the rack-bar, G, there is a cross-head, G2, projecting beyond the plane of the sides of the rack-bar which is provided with setscrews, g2, adapted to engage the rear ends of the bifurcated portion, D/of the knee, D, whereby the rack-bar, Gr, can be given a normal adjustment with relation to the knee, D.

In the rear portion of the knee, D, I mount an upright lever, J, upon a pivot, y', intermediate of its length, and from the lower end of the lever, J, there is a link J', which is pivoted to an ear, g3, on the upper edge of the rack-bar, G, and mount-ed in the rear portion of the knee, D, thereV is a dog, K, pivoted intermediate of its length on a pivot, 7c, which dog, K, is adapted to engage the section of rack-geanfg, on the upper edge of the .rack-bar, G, whereby the rack-bar, G, and knee, D, can be quickly adjusted with relation to each other, to suit the taper of a log, or for other purpose, and firmly retained in such temporary adjustment as longas may be'desired. For operating thedog, K, a grip-lever, L, is pivlla oted to the upper end of the lever, J, having a link, L, extending therefrom to the arm.

K, on the dog, K, and to prevent the accidental disengagement of the dog, K, I provide a spring, M, which operates on the end of said dog to retain it in engagement with the teeth, g, on the rack-bar, G.

In operation, when it is necessary to adjust the knee, D, somewhat forward so as to split a squared cant of timber into boards in such a manner that the last board will be of even thickness with the others, the knee, D, can be adjusted with relation to the rackbar, G, by means of the lever J, and dog, K, the operator can throw the knee forward or backward with relation to the rack-bar, G, for the purpose of overcoming the taper of a log so that the saw will cut a line parallel with the longitudinal center of the log, and the dog, K, when in engagement with the section of rack-gear, g, will iirmly retain the knee and rack-bar in the relative positions to which they have been so adjusted until it is desired to move them back to their normal position as established by the set-screws, g2 by means of the set-screws g2, in the rear of the rack-bar G, any lost motion between the dog K, and the rack-teeth G', on the rack-bar G, can be taken up. In all the other respects the head-block is operated in the usual manner.

Having thus described my invention so as to enable others to construct and utilize the same, what I claim as new and desire to secure by Letters-Patent is:

l. In a structure of the character described, head-block beams having longitudinal channels in their adjacent faces, a knee having a channel in the lower portion thereof, mechanism extending through the lower part of said knee and projecting into the channels in the head-block beams adapted to support said knee, and a rack-bar mounted in the channel in said knee and supported therein by the mechanism extending through and supporting said knee subst-antially as set forth.

2. In a structure of the character described, a bifurcated knee, transverse shafts pivoted in the lower bifurcated portion thereof, a rack-bar slidably mounted on said transverse shafts, teeth on said rack-bar,

dog mechanism pivoted in said knee and e11- gaging said teeth, means to operate said dog mechanism, and lever mechanism for adjusting said rack-bar with relation to said knee, substantially as set forth.

3.,Ina structure of the character described, a head-block having channels on the inside faces thereof, a knee operating on said block, rollers on said knee operating in the channels of the head-block, a-Xles passing through the knee and connecting said rollers, a rack-bar mounted on and carried by said axle within said knee and spaced therefrom, and setting-gear mounted in said head-block and engaging said rack-bar, substantially as set forth.

el. In a structure of the character described, head-block beams having channels therein, a bifurcated knee, transverse shafts journaled in the lower portion of said bifurcated knee, anti-friction devices on the ends of said shafts at each side of said knee operating in the channels in said head-block beams, a rack bar slidably supported within said knee upon said transverse shafts and spaced from each side of said knee, means to adjust said rack-bar with relation to said knee, means adapted to maintain said rackbar in adjusted position, and means to move said knee and rack-bar forward and back ward on said head-block beams, substantially as set forth.

In testimony whereof I affix my signature, in presence of two witnesses.

WILLIAM M. VILKIN. Witnesses:

H. M. SrURGnoN, P. V. GIFFORD.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

